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The species flock of haplochromine cichlid fishes in Lake Victoria is one of the most extensive and recent radiations of vertebrates known. Over the past 15 years, however, many of the haplochromine cichlid species have vanished, and predation by the introduced Nile perch (Lates niloticus) is thought to be one of the most significant factors underlying this mass extinction. Information on the hypoxia tolerance of haplochromines from the Lake Victoria is valuable for predicting their response to the increasing anoxia within the lake and in evaluating their potential use of low oxygen regions as refugia from predation by introduced Nile perch. This study examines the response of nine cichlid species from Lake Victoria (eight indigenous, one introduced) and three cichlid species from Lake Tanganyika to different low‐oxygen regimes under laboratory conditions. Fish were exposed to progressive and acute hypoxia, with and without access to the surface. All species used aquatic surface respiration at very low Po2. Buccal bubble holding and active swimming at the surface during aquatic surface respiration were used by many species and may serve to increase its efficiency. Lacustrine cichlids endemic to Lake Victoria were more tolerant of hypoxia than ecologically similar species from Lake Tanganyika. The two species examined that are widespread in variety of aquatic habitats exhibited a relatively high tolerance to hypoxia, with well‐developed aquatic surface respiration and bubble‐holding capabilities and no loss of equilibrium during progressive hypoxia. Species strongly affected by recent changes in Lake Victoria were not consistently poorer in their hypoxia tolerance than less‐affected species. But, two of the less‐affected species are inhabitants of shallow, rocky habitats, an environment that may be both rich in oxygen and well defended against the Nile perch because of the structural complexity of the rocky, littoral area. The generally high levels of hypoxia tolerance in the cichlid species examined from Lake Victoria suggest that these species potentially could use low‐oxygen refugia to escape Nile perch predation. Some species that are thought to have disappeared may currently inhabit low‐oxygen refugia that have not been adequately sampled. Tolerancia a la hipoxia en cíclidos del Africa oriental: Refugios con bajo contenido de oxígeno en el lago Victoria

Mangrove prop roots support diverse epibiont communities, but they are generally regarded as inhospitable for corals. However, recent reports have documented corals thriving on mangrove roots in the U.S. Virgin Islands and Cuba, and it has been proposed that mangroves may provide a refuge from environmental conditions that trigger coral mortality on nearby reefs. It also raises interesting questions about the potential evolutionary significance of coral populations in mangrove forest. We investigated diverse

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A miniature fiberoptic endoscope was used to observe the processes of particle encounter and retention inside the buccopharyngeal cavity of suspension-feeding tilapia. Small particles (38 µm to 1.0 mm in diameter) were trapped in strands and aggregates of mucus, which usually slid posteriorly on the ceratobranchials of arches I­IV towards the esophagus while the fish pumped water through the buccopharyngeal cavity. During stage 1 of periodic reversals of water flow inside the buccopharynx, mucus-bound particles usually lifted off the arch surfaces and travelled a short distance in an anterior or anterodorsal direction. During stage 2 of a reversal, the mucus usually resumed travel in a posterior or posteroventral direction and exited the field of view. Mucus was present less often during feeding on large particles (3­10 mm in diameter) than on small particles, and large particles were rarely observed to be attached to mucus. We discuss the advantages to suspension-feeding fishes of using aerosol filtration by mucus entrapment rather than sieving, and predict that many cichlid and cyprinid suspension feeders that consume bacteria and phytoplankton use mucus for aerosol filtration.